The radiological assessment of the Seabed option consists of estimating the detriment to man and to the environment that could result from the disposal of high-level nuclear waste within the seabed sediments in the deep oceans. The assessment is made for the high-level waste (vitrified glass) produced by the reprocessing of 10/sup 5/ tons of heavy metal from spent fuel, which represents the amount of waste generated by 3333 reactor-years of 900 MW(e) reactors, i.e., 3000 GW(E).a. The disposal option considered is to use 14,667 steel penetrators, each of them containing five canisters of HLW glass (0,15 m/sup 3/ each). These penetrators would reach a depth of 50 m in the sediments and would be placed at an average distance of 180 m from each other, requiring a disposal area on the order of 22 x 22 km. Two such potential disposal areas in the Atlantic ocean were studied, Great Meteor East (GME) and South Nares Abyssal Plains (SNAP). A special ship design is proposed to minimize transportation accidents. Approximately 100 shipments would be necessary to dispose of the proposed amount of waste. 1 ref.